1. Field of the Invention
The present invention relates to contact motion picture film printers and, in particular, relates to an improved film strip support shoulder for guiding film strips past the projection aperture.
2. Brief Description of the Prior Art
Prior art continuous contact motion film printers are designed to accommodate the printing of two different types of film formats. The two most common film formats are 16 mm film and 32 mm/35 mm film. The 32 mm/35 mm format is printed during the travel of the preprint film and raw stock film past a printing aperture or aperture jaw in one direction, or one path. The 16 mm film format is normally printed by first running the raw stock film through the printer in one direction past an aperture which is less than half the width of the previously discussed aperture. Then the raw stock film is turned around and run through the printer in the opposite direction exposing the other half of the 35 mm film with the same aperture.
In some prior film printers, the printing head was designed to operate in both modes, having a two position aperture jaw, one for printing the 32/35 mm format and one for printing the 16 mm format. However, in most of these prior art printers, a solid guide rail is used at approximately the midpoint of the raw stock film strip for supporting the center thereof to provide an accurate printing since the preprint film, being of the 16 mm size, needs support on its edge opposite the film strip. Although the design of these guide rails was optimized to provide high quality surface finishes, there is considerable film damage caused by these stationary rails. In addition, current highspeed film printers will generate sufficient frictional heat between the film and the solid rail to severely damage the preprint film which, in some cases, cannot be reproduced.